The present invention relates to an improvement of a door camera unit for imaging visitors, for example, set so as to direct an imaging direction to a neighborhood of an entrance of a building.
As to this kind of prior art techniques, there are known television interphones such as the one disclosed in JP-A-Hei 5-308638. By these prior art techniques, visitors, for example, are imaged by means of a television camera whose video signals are taken in by a television monitor to be displayed. The whole device is so constructed that there are disposed A/D converting means, a video memory, signal processing means and D/A converting means on signal lines connecting the television monitor with the television camera; that the video signals from the television camera are converted into digital data by means of the A/D converting means and digital video data are stored temporarily in the video memory, that thereafter they are subjected to video distortion correction by means of the signal processing means and enlarging processing and converted again to analogue signals by means of the D/A converting means; and finally they are inputted to the television monitor.
However, the video memory according to the prior art is a device for storing strictly temporarily video data in order to subject them to video distortion correction, enlarging processing, etc. and it is not constructed for recording or conservation of the video data. For this reason, according to the prior art techniques, it was not possible to image doubtful visitors, etc. and leave video image""s thereof for the sake of security, i.e. safety. In a general security system, video images are recorded by means of a video recorder. In cases where they are recorded by means of a video recorder, unnecessary video images are also recorded, requiring not only a lot of time searching a necessary video image, but also makes it impossible to assemble the door camera unit and the recording means in one body in a compact manner.
The present invention has been made in order to solve the above problem and an object thereof is to provide a door camera unit having recording means, which includes a video memory, in which only necessary video images are automatically recorded.
In order to solve the above problem of the prior art, according to the present invention, a door camera unit whose imaging direction is directed to a neighborhood of an entrance of a building, has a video memory in which an information inputting section is connected with the door camera unit, the section of which outputs information signals for judging whether video images should be recorded or not. The video memory for recording records every time an information signal inputted from the information inputting section to the door camera unit meets video image recording execution conditions.
In the invention described above, the information inputting section may include a chime switch operated by a visitor and a video image may be recorded in the video memory every time an operation signal inputted from the information inputting section to the door camera unit meets video image recording execution conditions.
In the invention described above, the information inputting section may include a chime switch operated by a visitor and a human body detecting sensor detecting access of the visitor, an image of whom may be recorded in the video memory unless an operation signal is inputted from the chime switch in a predetermined period of time after a detection signal has been inputted from the human body detecting sensor.